The Overactive Bladder

From Therapeutic Advances in Urology
Posted: 03/11/2011; Ther Adv Urol. 2010;2(4):147-155

Richard Foon, MRCOG; Marcus J. Drake, MA, DM, FRCS (Urol)

Abstract

Urinary urgency and the associated symptoms which comprise overactive bladder are prevalent amongst the general population and adversely affect quality of life. Disease management consists of a sequential series of options starting with behavioural and lifestyle techniques, pharmacological management (antimuscarinics) and, in severe cases, surgical treatment (urinary diversion, neuromodulation, augmentation cystoplasty and detrusor myectomy).
There is increasing recognition of pathophysiological mechanisms in the urothelium, interstitial cells and afferent neurons allowing the importance of peripheral integrative interaction to be identified. The hierarchy of the central nervous system control adds additional complexity to understanding the oflower urinary tract function. Some newer methods of treatment include Botulinum toxin A intramural injections, oral beta-3 adrenergic agonists and rho-kinase inhibitors. The lack of a disease generating hypothesis, the lack of animal models for disease and the subjective nature of the central symptom (urgency) still pose considerable theoretical and scientific hurdles that need to be overcome in the treatment of this condition.
Introduction

Overactive bladder syndrome (OAB) is the presence of urinary urgency, usually with frequency and nocturia, in the absence of other causes of similar symptoms.
It is essential to consider urinary tract infection or pelvic malignancy as a potential cause. The following are definitions of some of the key terms [Abrams et al. 2002]:

1. Urgency: the complaint of a sudden compelling desire to pass urine, which is difficult to defer.
2. Detrusor overactivity (DO): a urodynamic observation characterized by involuntary detrusor contractions during the filling phase, which may be spontaneous or provoked (Figure 1).
3. Increased daytime frequency: a complaint by the patient who considers that he/she voids too often by day.
4. Nocturia: the complaint that the individual has to wake at night one or more times to void.

If there is associated urgency incontinence, the term 'OAB wet' can be used; if there is no urgency incontinence then the term 'OAB dry' is appropriate [Stewart et al. 2003].
Urgency is the symptom with greatest impact on quality of life [Coyne et al. 2008] and hence is one of the main issues with regards to the clinical management.
It is important to note that not all patients present with both frequency and urgency. In fact, frequency might in some people be a compensatory mechanism by which the bladder is prevented from filling to a volume where urgency occurs.
As a result some patients may present with minimal urgency, despite urgency being the defining symptom of OAB; they will, though, manifest frequent voiding of small volumes.

Lower urinary tract symptoms (LUTS) in general are highly prevalent [Coyne et al. 2009] while it is estimated that the prevalence of OAB is approximately 12%, increasing with age, and somewhat similar prevalence in males and females [Irwin et al. 2006]. As far as the financial cost is concerned, OAB has a significant impact, costing billions of euros for clinical, social and occupational management [Reeves et al. 2006].

rest of article - http://www.medscape.com/viewarticle/738698_8

Conclusions

Conservative management, supplemented by antimuscarinic drugs, should be instigated following simple evaluation. Where symptoms persist, urodynamic diagnosis is appropriate. A number of invasive treatments are available, but the evidence base is patchy and potential morbidity and cost can be substantial. Development of new treatments based on a growing wealth of experimental data is promising, but many challenges remain.